The invention relates to a shaft of a tool or the like according to the preamble of claim 1.
Tools provided with shafts are used in various spheres of life from work to hobbies. What is relevant to the function and use of equipment provided with long shafts is the length of their shafts. Different applications and users require different shaft lengths, and thus it is often advantageous to provide a tool with an adjustable shaft, which allows each user to adjust the shaft length to suit him/her and the application. The use of adjustable shafts in tools provided with long shafts is a prior art solution. Adjustable shafts are used, for example, in shovels, mops and crutches. Furthermore, sticks and poles with long shafts are used in various sports, such as floorball sticks, ski poles and Nordic walking poles which have an adjustable length. Adjustability of the shaft length allows the length of equipment to be adjusted according to each user and application, which facilitates carrying out of the task at hand. Traditionally, problems associated with the shaft length have been solved by interchangeable handles of different lengths or by mechanisms enabling the adjustment of the shaft length.
When the shaft length is adjusted by means of adjusting mechanisms, the sections of the shaft consisting of two separate sections move inside each other so that the tool shaft can be shortened by pushing one section of the shaft inside the other and lengthened by pulling the sections within each other apart in opposite directions. The shaft length can be adjusted and the shaft locked at the desired length by an adjusting mechanism which is provided in the shaft and by which the shaft sections can be locked into the desired position and released for the adjustment of the shaft length. An example of a mechanism for adjusting the length of a tool shaft is described in U.S. Pat. No. 1,411,195. The length of the shovel shaft described in this publication can be adjusted by a movable upper shaft. The upper shaft is partly provided inside a hollow tubular lower shaft, and it can be tightened to the desired position by a clamping band. An example of another adjusting mechanism based on friction is disclosed in U.S. Pat. No. 5,460,458. U.S. Pat. No. 5,795,000 describes an adjusting mechanism based on a spring pin arrangement where the outer shaft section is provided with appropriately spaced holes and the user arranges the spring pin provided in the inner shaft section in the desired hole when adjusting the length of the tool shaft.
A problem associated with the solutions described above is that adjusting mechanisms based on friction cannot usually hold the tool shaft in place sufficiently tightly during use or they loosen during use. Furthermore, such tools are often stored outside, and therefore the metal parts of the spring pin arrangement may rust and become useless.